Metatarsal pad mounting for weight distributing shoe shank

ABSTRACT

A spring steel shoe shank interposed between the inner and outer sole of a shoe, which shank has a metatarsal pad mounted thereon to overlie and extend both forwardly and rearwardly beyond a transversely elongated forward metatarsal arch supporting portion of the shank. The shank has an intermediate portion of reduced width and a rear portion wider at its maximum width adjacent its forward end than said intermediate portion. The rear portion inclines gradually upwardly transversely toward the inner edge of the shank. The shank has a rectangular transversely extending slot in the forward transversely elongated portion and the metatarsal pad has a rectangular transversely extending rib closely fitting the slot to hold the metatarsal pad against shifting relative to the shank. The intermediate portion of the shank may have a longitudinal stiffening rib that extends into the forward and rear shank portions.

United States Patent 1 [111 3,841,005

Cox Oct. 15, 1974 METATARSAL IAll) MOUNTING FOR WEIGHT DISTRIBUTING SHOESHANK Primary Examiner-Patrick D. Lawson [57] ABSTRACT A spring steelshoe shank interposed between the inner and outer sole of a shoe, whichshank has a metatarsal pad mounted thereon to overlie and extend bothforwardly and rearwardly beyond a transversely elongated forwardmetatarsal arch supporting portion of the shank. The shank has anintermediate portion of reduced width and a rear portion wider at itsmaxi mum width adjacent its forward end than said intermediate portion.The rear portion inclines gradually upwardly transversely toward theinner edge of the shank. The shank has a rectangular transverselyextending slot in the forward transversely elongated portion and themetatarsal pad has a rectangular transversely extending rib closelyfitting the slot to hold the metatarsal pad against shifting relative tothe shank. The intermediate portion of the shank may have a longitudinalstiffening rib that extends into the forward and rear shank portions.

12 Claims, 9 Drawing; Figures METATARSAL PAD MOUNTING FOR WEIGHTDISTRIBUTING SHOE SHANK My invention relates to weight distributing shoeshanks of tempered steel that are provided with a metatarsal pad. Thepresent invention is an improvement over that disclosed in my US. Pat.No. 2,811,790 patented Nov. 5, 1957 on Weight Distributing Shoe Shank.

My aforesaid patent had for its purpose to provide a shoe shank, builtinto a shoe between the outer and inner sole, that controls the bonestructure of the foot so as to distribute the weight of the body on thefoot structure in the way that it would be naturally supported, if thenormal foot were in engagement with the ground, or some other supportingsurface, without being encased in a shoe. When the normal foot that isnot encased in a shoe starts into forward motion the weight of the bodyis first thrown on the heel bone or foot forwardly of the heel onto theouter longitudinal arch and finally on the ball of the foot ormetatarsal arch. Because shoes have heels thereon this normal actiondoes not ordinarily occur and the outer longitudinal arch of the foot isput under a strain which produces weakness thereof and malalignment ofthe arch bones, and further causes the longitudinal arch of the foot toweaken and the foot to roll inwardly or pronate, throwing the inner edgeportion of the foot into a lower than normal position. Because the footstructure is not in normal position the two lower leg bones are throwninto a twisted or unnatural position, which causes the legs to appear tobe knockkneed.

The purpose of my shoe shank disclosed in my US. Pat. No. 2,811,791 isto control or support the bone structure of the foot to produce a normalor natural weight balancing. Since the heel bone or oscalcis is thelargest bone of the foot, it is necessary that it be held in its correctposition to avoid its twisting, rotating or pronating. This isaccomplished in my patented shoe shank by providing means for elevatingthe inner forward position of the heel of the foot so as to roll theweight to the outer side of the foot or to the outer longitudinal arch.A longitudinal arch supporting portion is provided in my patented shoeshank adjacent the outer side of the insole between the forward end ofthe heel portion of the shank and the forward metatarsal arch or ballsupporting portion of the shank.

The shank disclosed in my US. Pat. No. 2,811,791 is provided with atransversely elongated forward metatarsal arch supporting portion, thatextends from the forward end of the longitudinal arch supporting portionunder all of the bones of the metatarsal arch structure, and is domedupwardly from adjacent the side edges and forward and rear edges thereofto a central point.

The present invention utilizes the basic structure of the shankdisclosed in my US. Pat. No. 2,811,791 to control and support the bonestructure of the foot to produce a normal weight bearing including thesupport of the bones of the metatarsal arch structure in their ears thatflatly engage the insole above the shoe heel, but inclines upwardlytransversely toward the inner side edge thereof, thus throwing theweight at the heel of the foot toward the outside of the foot and toward5 the outer longitudinal arch. Said shoe shank is of such a structurethat the longitudinal arch supporting portion thereof, being locatedalong the outer side of the insole, does not restrict the musclefunctions or purpose of the inner longitudinal arch, allowing it toperform its intended function of acting as a spring or shock absorberfor thebody.

It has been found that there are many foot conditions, usually resultingfrom improper support of the body weight by the bones of the foot, thatmake it desirable to raise the second, third and fourth metatarsal archbones higher relative to the first and fifth bones of the metatarsalarch than can be accomplished by a shank structure such as thatdisclosed, in my US. Pat. No. 2,811,791. To provide such a raisedposition for the second, third and fourth metatarsal arch bones Iprovide a metatarsal pad in combination with my shoe shank whichprovides such a raised position for said second, third and fourthmetatarsal bones without interfering in any respect with the functionsof providing normal and natural weight balancing of the shank disclosedin said patent.

In order to have such a metatarsal pad operate properly in relation tothe metatarsal arch of the foot it must be held in the proper positionwith respect to the bones of the metatarsal arch and the spring steelshank. I accomplish this by providing the spring steel shoe shank of thecharacter above described with a metatarsal pad that is mounted on theforward metatarsal arch supporting portion of the shank and providingsaid transversely elongated forward metatarsal arch supporting portionof the shank and the metatarsal pad with interengaging means for holdingthe pad in proper position I with respect to the transverse archsupporting portion of the shank. The means that is provided for thispurpose is of such a character that it prevents any shifting of the padrelative to the shank or twisting thereof out of position relative tothe shank by providing a transversely extending rectangular slot in theforward transversely elongated shank portion and a rectangulartransversely extending rib on the metatarsal pad closely fitting in theslot. The pad is preferably so formed that it tapers toward the edgesthereof from the midportion thereof and has such an area that it extendsboth forwardly and rearwardly beyond the forward transversely elongatedshank portion, the extending portions being in the tapering portion ofthe pad. Since the shank has a predetermined fixed position in respectto both the insole and outsole of the shoe, the metatarsal pad will havea fixed position, which is the most desirable position for such a pad,with respect to the insole of the shoe and thus with respect to the:bones of the foot of the wearer of a shoe that has my patented steelshank that is provided with the metatarsal pad, incorporated therein.

Other objects and advantages of my invention will appear as thedescription of the drawings proceeds. I desire to have it understood,however, that I do not intend to limit myself to the particular detailsshown or described except as defined in the claims.

IN THE DRAWINGS:

FIG. 1 is a bottom plan view of a shoe, showing my improved shank andmetatarsal pad thereon, mounted in position in the shoe in dottedoutline.

FIG. 2 is a fragmentary enlarged vertical sectional view taken on theline 2-2 of FIG. 1, the shoe upper being broken away.

FIG. 3 is an enlarged fragmentary sectional view taken on the line 33 ofFIG. 1.

FIG. 4 is a diagrammatic view showing the bones of the foot in dottedoutline and the outline of the shoe, my weight distributing shank andmetatarsal pad in full lines in relation to the foot bone structure.

FIG. 5 is a bottom plan view of the metatarsal pad detached.

FIG. 6 is a similar view partly broken away of my shoe shank to whichthe metatarsal pad is to be applied.

FIG. 7 is a fragmentary vertical sectional view taken on the line 77 ofFIG. 1 through the insole, outsole and the spring steel shank.

FIG. 8 is a section taken on the line 88 of FIG. 5, and FIG. 9 is asection taken on the line 99 of FIG. 5.

Referring in detail to the drawings, my improved shoe shank comprises aforward metatarsal arch supporting portion 10, an intermediatelongitudinal arch supporting portion 11, and a rear portion 12. Saidrear portion 12 comprises rearwardly extending attaching ears l3 and 14,the ear 13 being longer than the ear l4 and extending rearwardly beyondthe rear end edge of the ear 14, the ears being spaced to provide anopening or cutout portion 15 for the nailing of a rubber heel to theinsole between said ears.

The rear portion 12 gradually widens toward its junction with thelongitudinal arch supporting portion 11. The outer marginal edge 16 ofmy shank extends substantially parallel of the outer edge of the outsoleand insole, the outsole being indicated by the numeral 17 in FIGS. 2, 3and 7. The rear portion 12 inclines upwardly transversely from a pointsubstantially at the transverse middle of the rear portion in alignmentwith the cutout portion 15 to the junction 18 thereof, with thelongitudinal arch supporting portion 11, the inclined portion beingindicated in FIG. 7 by the numeral 19. Thus the junction 18 of thelongitudinal arch supporting portion 11 with the rear portion 12 iselevated about one-fourth of an inch higher than the outer edge portion20 thereof. The ears l3 and 14, however, are flat and engage the outsolel7 flatly, as well as the insole 21.

The longitudinal arch supporting portion 11 of said shoe shank has aslightly concavely curved inner edge 22 and an outer longitudinal edge23 which is very slightly concavely curved so as to extend substantiallyparallel to and near the outer edge portion of the outsole. Thus themajor portion of the longitudinal arch supporting portion 11 of my shoeshank lies on the outer side of the centerline of the shoe, the onlyportion thereof that lies inwardly of said centerline being thegradually widening portion that joins it with the rear portion 12. Iffound desirable, the longitudinal arch supporting portion may bestiffened by providing a rib 24 by means of a currugation therein whichhas a forward curved end portion 25 extending into the forwardtransverse metatarsal arch supporting portion 10, and a pair oftransversely spaced portions 26 and 27 at the rear end thereof extendinga short distance into the rear portion 12.

The forward metatarsal supporting portion 10 extends transversely thefull width of the metatarsal arch structure of the foot underlying allthe bones of the metatarsal arch shown in FIG. 4. It is of atransversely elongated substantially elliptical character having aconvexly curved inner end edge portion 28 and joins with the outer edge23 of the longitudinal arch supporting member 11 in a smooth convexcurve 29 and with the inner edge 22 of said longitudinal arch supportingmember in a smooth concave curve 30. Said metatarsal arch supportingportion 10 is of a concave-convex character, being domed upward orcurved upwardly from all the side edges thereof toward the centerthereof, the domed up portion being indicated generally by the numeral31. Said domed portion curves upwardly from the inner and outer edgesthereof toward the middle thereof, as shown in FIG. 2, and from theforward and rear edges thereof, as shown in FIG. 3. Preferably theportion 10' is raised about one-sixteenth of an inch adjacent themarginal edges thereof, and to about three-sixteenth of an inch at itshighest elevation at the center of the domed portion 31 of the forwardtransverse metatarsal arch supporting portion 10.

The forward transverse metatarsal arch supporting portion 10 isprovided, at its center at the highest elevation of said domed portion,with a transversely extending slot 32 which has straight parallel sidewalls 33 and straight parallel end walls 34 that extend perpendicular tosidewalls 33. A metatarsal pad 35 is mounted on the spring steel shoeshank on the forward transverse metatarsal arch supporting portion 10thereof, being made of a molded plastic material which is slightlyyieldable so as to have a cushioning action, and has integrally formedthereon a rib 36 projecting downwardly from the bottom face of said pad,said rib 36 having straight parallel sidewalls 33 and straight parallelend walls 34' extending perpendicularly to the walls 33'. Said rib is ofthe same size as the slot 32, having the same width and length, andfitting in the slot 32 closely.

The pad 35 has an approximately oval body portion which has a bluntforward end portion 37 and a rearwardly extending portion 38 whichgradually tapers in width and thickness rearwardly from substantiallythe maximum transverse diameter of said pad. The maximum transversediameter of the pad is positioned over the transversely elongatedforward portion 10 of the shank and the rib 36 on said pad liessubstantially on the maximum transverse diameter of the pad. The bodyportion of the pad has tapering marginal portions around the entireperiphery of said body portion, the tapering edge portions beingindicated in FIGS. 2, 3, 8 and 9 by the numeral 39. Except for the rib36 the bottom face 40 of the pad, before assembly with the shank, isflat, while the top surface of the pad curves gradually bothtransversely and longitudinally of the pad from the maximum thickness 41thereof, having a rather sharply curved end portion 42 on the bluntforward end thereof and a gradually downwardly inclining top wall 43 onthe portion thereof extending rearwardly from the portion of maximumthickness of said pad to the thin tapered peripheral edge portion 39 atthe rear end thereof. The pad also has the top surface thereof curveddownwardly transversely, as shown at 44 in FIG. 9, from the midportionof maximum thickness thereof to the peripheral edge 39.

A metatarsal pad is thus provided that has a blunt forward end 37 whichextends forwardly beyond the transversely elongated portion of the shankand a portion 38 that gradually tapers in width and thickness extendingrearwardly from the portion of maximum thickness and maximum transversediameter of said pad to the rear edge portion thereof. The portion 38extends rearwardly beyond the transversely elongated portion 10 of theshank and overlies the extreme forward end of the longitudinal archsupporting portion of the shank. The pad is thus spaced forwardlysubstantially the length of said intermediate longitudinal archsupporting portion 11 from the rear portion of the shank. This spacesthe transversely inclined forward end of the rear portion of the shank asubstantial distance from the metatarsal pad 35 so that the shank willnot have its function of throwing the weight on the heel of the foottoward the outside of the foot interfered with by the provision of themetatarsal pad. Preferably a wedge shaped filler member is placed on theoutsole and secured thereto before placing the shank in position. Thefiller member is located under the upwardly inclined portion 19 of therear portion 12 of the shank.

The metatarsal pad 35 is positioned under the second, third and fourthbones of the metatarsal arch to raise and support the same in a normalposition.

- What I claim is:

l. The combination with a spring steel shoe shank mounted between theinner and outer shoe sole of a metatarsal pad mounted on said shank,said shank having a transversely elongated forward portion, anintermediate longitudinal arch supporting portion and a rear portion,said pad overlying said transversely elongated forward portion andextending both forwardly and rearwardly beyond said forward portion, andinterfitting means on said pad and said forward portion of said shank tohold said pad against shifting relative to said shank.

2. The combination claimed in claim 1 in which said interfitting meanscomprises a rib on said pad fitting in a slot in said shank.

3. The combination claimed in claim 2 in which said rib and slot arerectangular and extend transversely of said pad and shank respectively.

4. The combination claimed in claim 1 in which said pad has a bodyportion tapering in thickness toward the marginal edges thereof and saidtapering marginal portions extend both forwardly and rearwardly beyondsaid forward transversely elongated shank portion.

5. The combination claimed in claim 1 in which said shank has a rearportion inclined gradually upwardly toward the inside of said shankspaced from said pad, said pad has an approximately oval body portionthe maximum transverse diameter of which is positioned over saidtransversely elongated forward portion of said shank, has a bluntforward end extending forwardly beyond said transversely elongatedportion of said shank and a portion gradually tapering rearwardly inwidth and thickness extending rearwardly beyond said transverselyelongated portion of said shank, said gradually tapering rearwardlyextending portion of said pad ex tending over the forward end of saidlongitudinal arch supporting portion in forwardly spaced relation tosaid rear portion of said shank.

6. The combination with a spring steel shoe shank mounted between theinner and outer shoe sole of a metatarsal pad mounted on said shank,said shank having a transversely elongated forward portion, anintermediate longitudinal arch supporting portion and a rear portion,said pad overlying said transversely elongated forward portion andinterfitting means on said pad and said forward portion of said shank tohold said pad against shifting relative to said shank, said pad havingan approximately oval body portion the maximum transverse diameter ofwhich is positioned over said transversely elongated forward portion ofsaid shank. 7. The combination claimed in claim 6 in which said pad hasa blunt forward end extending forwardly beyond said transverselyelongated portion of said shank.

8. The combination claimed in claim 6 in which said pad has a bluntforward end extending forwardly beyond said transversely elongatedportion of said shank and a portion gradually tapering rearwardly inwidth and thickness extending rearwardly beyond said transverselyelongated portion of said shank.

9. The combination claimed in claim 6 in which said pad has a bluntforward end extending forwardly beyond said transversely elongatedportion of said shank and a portion gradually tapering rearwardly inwidth and thickness extending rearwardly beyond said transverselyelongated portion of said shank, said gradually tapering rearwardlyextending portion of said pad extending over the forward end of saidlongitudinal arch supporting portion.

10. The combination claimed in. claim 6 in which said body portion ofsaid pad tapers in. thickness toward the marginal edges thereof and saidtapering marginal portions extend both forwardly and rearwardly beyondsaid forward transversely elongated shank portion.

11. The combination claimed in claim 10 in which said pad has a bluntforward end extending forwardly beyond said transversely elongatedportion of said shank.

12. The combination claimed in claim 10 in which said pad has a bluntforward end extending forwardly beyond said transversely elongatedportion of said shank and a portion gradually tapering rearwardly inwidth extending rearwardly beyond said transversely elongated portion ofsaid shank.

1. The combination with a spring steel shoe shank mounted between theinner and outer shoe sole of a metatarsal pad mounted on said shank,said shank having a transversely elongated forward portion, anintermediate longitudinal arch supporting portion and a rear portion,said pad overlying said transversely elongated forward portion andextending both forwardly and rearwardly beyond said forward portion, andinter-fitting means on said pad and said forward portion of said shankto hold said pad against shifting relative to said shank.
 2. Thecombination claimed in claim 1 in which said interfitting meanscomprises a rib on said pad fitting in a slot in said shank.
 3. Thecombination claimed in claim 2 in which said rib and slot arerectangular and extend transversely of said pad and shank respectively.4. The combination claimed in claim 1 in which said pad has a bodyportion tapering in thickness toward the marginal edges thereof and saidtapering marginal portions extend both forwardly and rearwardly beyondsaid forward transversely elongated shank portion.
 5. The combinationclaimed in claim 1 in which said shank has a rear portion inclinedgradually upwardly toward the inside of said shank spaced from said pad,said pad has an approximately oval body portion the maximum transversediameter of which is positioned over said transversely elongated forwardportion of said shank, has a blunt forward end extending forwardlybeyond said transversely elongated portion of said shank and a portiongradually tapering rearwardly in width and thickness extendingrearwardly beyond said transversely elongated portion of said shank,said gradually tapering rearwardly extending portion of said padextending over the forward end of said longitudinal arch supportingportion in forwardly spaced relation to said rear portion of said shank.6. The combination with a spring steel shoe shank mounted between theinner and outer shoe sole of a metatarsal pad mounted on said shank,said shank having a transversely elongated forward portion, anintermediate longitudinal arch supporting portion and a rear portion,said pad overlying said transversely elongated forward portion andinterfitting means on said pad and said forward portion of said shank tohold said pad against shifting relative to said shank, said pad havingan approximately oval body portion the maximum transverse diameter ofwhich is positioned over said transversely elongated forward portion ofsaid shank.
 7. The combination claimed in claim 6 in which said pad hasa blunt forward end extending forwardly beyond said transverselyelongated portion of said shank.
 8. The combination claimed in claim 6in which said pad has a blunt forward end extending forwardly beyondsaid transversely elongated portion of said shank and a portiongradually tapering rearwardly in width and thickness extendingrearwardly beyond said transversely elongated portion of said shank. 9.The combination claimed in claim 6 in which said pad has a blunt forwardend extending forwardly beyond said transversely elongated portion ofsaid shank and a portion gradually tapering rearwardly in width andthickness extending rearwardly beyond said transversely elongatedportion of said shank, said gradually tapering rearwardly extendingportion of said pad extending over the forward end of said longitudinalarch supporting portion.
 10. The combination claimed in claim 6 in whichsaid body portion of said pad tapers in thickness toward the marginaledges thereof and said tapering marginal portions extend both forwardlyand rearwardly beyond said forward transversely elongated shank portion.11. The combination claimed in claim 10 in which said pad has a bluntforward end extending forwardly beyond said transversely elongatedportion of said shank.
 12. The combination claimed in claim 10 in whichsaid pad has a blunt forward end extending forwardly beyond saidtransversely elongated portion of said shank and a portion graduallytapering rearwardly in width extending rearwardly beyond saidtransversely elongated portion of said shank.